fileinfo: implement os_fileinfo_size

this replaces os_get_file_size and file_info.stat.st_size

src/nvim/diff.c

@@ -947,9 +947,10 @@ void ex_diffpatch(exarg_T *eap)
   os_remove((char *)buf);
 
   // Only continue if the output file was created.
-  off_t file_size;
+  FileInfo file_info;
-  bool file_size_success = os_get_file_size((char *)tmp_new, &file_size);
+  bool info_ok = os_get_file_info((char *)tmp_new, &file_info);
-  if (!file_size_success || file_size == 0) {
+  off_t filesize = os_fileinfo_size(&file_info);
+  if (!info_ok || filesize == 0) {
     EMSG(_("E816: Cannot read patch output"));
   } else {
     if (curbuf->b_fname != NULL) {

src/nvim/eval.c

@@ -9165,15 +9165,16 @@ static void f_getfsize(typval_T *argvars, typval_T *rettv)
 
   rettv->v_type = VAR_NUMBER;
 
-  off_t file_size;
+  FileInfo file_info;
-  if (os_get_file_size(fname, &file_size)) {
+  if (os_get_file_info(fname, &file_info)) {
+    off_t filesize = os_fileinfo_size(&file_info);
     if (os_isdir((char_u *)fname))
       rettv->vval.v_number = 0;
     else {
-      rettv->vval.v_number = (varnumber_T)file_size;
+      rettv->vval.v_number = (varnumber_T)filesize;
 
       /* non-perfect check for overflow */
-      if ((off_t)rettv->vval.v_number != file_size) {
+      if ((off_t)rettv->vval.v_number != filesize) {
         rettv->vval.v_number = -2;
       }
     }

src/nvim/fileio.c

@@ -5127,9 +5127,10 @@ void buf_reload(buf_T *buf, int orig_mode)
 }
 
 void buf_store_file_info(buf_T *buf, FileInfo *file_info)
+  FUNC_ATTR_NONNULL_ALL
 {
   buf->b_mtime = (long)file_info->stat.st_mtim.tv_sec;
-  buf->b_orig_size = file_info->stat.st_size;
+  buf->b_orig_size = os_fileinfo_size(file_info);
   buf->b_orig_mode = (int)file_info->stat.st_mode;
 }
 

src/nvim/memline.c

@@ -1632,7 +1632,7 @@ void ml_sync_all(int check_file, int check_char)
       FileInfo file_info;
       if (!os_get_file_info((char *)buf->b_ffname, &file_info)
           || file_info.stat.st_mtim.tv_sec != buf->b_mtime_read
-          || (off_t)file_info.stat.st_size != buf->b_orig_size) {
+          || os_fileinfo_size(&file_info) != buf->b_orig_size) {
         ml_preserve(buf, FALSE);
         did_check_timestamps = FALSE;
         need_check_timestamps = TRUE;           /* give message later */

src/nvim/os/fs.c

@@ -258,20 +258,6 @@ int os_file_is_writable(const char *name)
   return 0;
 }
 
-/// Get the size of a file in bytes.
-///
-/// @param[out] size pointer to an off_t to put the size into.
-/// @return `true` for success, `false` for failure.
-bool os_get_file_size(const char *name, off_t *size)
-{
-  uv_stat_t statbuf;
-  if (os_stat(name, &statbuf)) {
-    *size = statbuf.st_size;
-    return true;
-  }
-  return false;
-}
-
 /// Rename a file or directory.
 ///
 /// @return `OK` for success, `FAIL` for failure.
@@ -408,6 +394,15 @@ uint64_t os_file_info_get_inode(const FileInfo *file_info)
   return file_info->stat.st_ino;
 }
 
+/// Get the size of a file from a `FileInfo`.
+///
+/// @return filesize in bytes.
+off_t os_fileinfo_size(const FileInfo *file_info)
+  FUNC_ATTR_NONNULL_ALL
+{
+  return file_info->stat.st_size;
+}
+
 /// Get the `FileID` for a given path
 ///
 /// @param path Path to the file.

test/unit/os/fs_spec.lua

@@ -597,6 +597,20 @@ describe('fs function', function()
       end)
     end)
 
+    describe('os_fileinfo_size', function()
+      it('returns the correct size of a file', function()
+        local path = 'unit-test-directory/test.file'
+        local file = io.open(path, 'w')
+        file:write('some bytes to get filesize != 0')
+        file:flush()
+        file:close()
+        local size = lfs.attributes(path, 'size')
+        local file_info = file_info_new()
+        assert.is_true(fs.os_get_file_info(path, file_info))
+        eq(size, fs.os_fileinfo_size(file_info))
+      end)
+    end)
+
     describe('os_get_file_id', function()
       it('returns false if given an non-existing file', function()
         local file_id = file_id_new()